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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // var s = '[1,2,3]'
        // var data = JSON.parse(s)
        // console.log(data);
        class Star {
            constructor(name, age) {
                this.name = name;
                this.age = age;
            }
            bi(num) {
                console.log(this.age+num,this);

            }
        }
        class sing extends Star {
            constructor(name,age){
   super(name,age)
            }
            bi(num){
                super.bi(num)
            }
        }
        // var ldh = new Star('liudeg', 12)
        // ldh.bi(4);
        // console.log(ldh.name);
     var zjl = new sing('z',13)
     zjl.bi(3)
    </script>
</body>

</html>